V6NetHandle: NET6-2001-500-4-1 OrgID: ARINOPS Parent: NET6-2001-400-0 NetName: ARIN-ASH NetRange: 2001:500:4:: - 2001:500:4:FFFF:FFFF:FFFF:FFFF:FFFF NetType: assignment OriginAS: 10745 RegDate: 2006-03-13 Updated: 2016-04-18 Source: ARIN OrgID: ARINOPS OrgName: ARIN Operations CanAllocate: Street: PO Box 232290 City: Centreville State/Prov: VA Country: US PostalCode: 20120 RegDate: 2012-09-07 Updated: 2016-08-08 OrgAbuseHandle: AOA4-ARIN OrgTechHandle: NEWTO24-ARIN OrgAdminHandle: KOSTE6-ARIN OrgTechHandle: MJO282-ARIN OrgTechHandle: ROWLE12-ARIN Source: ARIN
IP address ranges, or netblocks, are groups of related IP addresses. They are usually represented as a base IP address, followed by a slash, and then a netmask which represents how many IP addresses are contained within the netblock. This format is known as CIDR. You'll also sometimes see netblocks given as a start ip address, and an end ip address, or an ip address range.
Traffic works its way around the internet based on the routing table, which contains a list of networks and their associated netblocks.